(a) Field of the Invention
The present invention relates to a display device, and more particularly to a dual display device.
(b) Description of the Related Art
Generally, a liquid crystal display device includes a pair of panels provided with pixel electrodes and a common electrode, and a liquid crystal layer with dielectric anisotropy interposed between the panels. The liquid crystal display device controls the transmittance of light passing through the liquid crystal layer by applying an electric field to the liquid crystal layer and adjusting the field strength for displaying desired images.
Because the LCD device is a light-receiving device which is incapable of self-emitting light, light emitted by lamps of a separately provided backlight unit passes through the liquid crystal layer, or external light, such as natural light, passes through the liquid crystal layer twice by reflection. The first described LCD device is called a “transmissive” type of LCD device and the latter described LCD device is called a “reflective” type of LCD device. The reflective type of LCD device is commonly used in medium and small display devices. Another type of LCD device is a “transflective” or “reflective-transmissive” LCD device which is capable of selectively using light from the backlight unit and external light in response to existing circumstances. The transflective LCD device is commonly used in medium and small display devices.
In the transflective LCD device, each pixel has a transparent electrode and a reflective electrode electrically connected to each other. The light emitted from the backlight unit passes through the transparent electrode for use in display and the external light entering from the opposite side of the backlight unit is reflected from the reflective electrode for use in display. Therefore, images are always displayed on only one surface of the liquid crystal panel assembly.
Accordingly, in this case, when the liquid crystal panel assembly is viewed from the other opposite side surface, an image whose left and right are reversed is seen.
When it is desired to display an image on both side surfaces in a mobile phone or the like, two liquid crystal panel assemblies overlap each other so that only the outer surfaces of each of the two liquid crystal panel assemblies are used for display. However, although an image can be displayed on both sides of the display device, the thickness of the overall display device is larger.